As computer systems grow in speed and shrink in size, power consumed within the computer per unit volume (power density) increases dramatically. Thus, it becomes evermore important to dissipate the heat generated by components within the computer during operation to ensure that the components remain within their normal operating temperature ranges. This reduces a chance that the components will fail immediately or have too short a lifetime.
In early desktop personal computers, components were passively cooled by radiation or convection, the surfaces of the components themselves interfacing directly with still air surrounding the component to transfer heat thereto. Unfortunately, air is not a particularly good conductor of heat. Therefore, in the early desktop computers, the heated air tended to become trapped, clinging to the components, acting as a thermal insulator and increasing component operating temperature. Eventually, computers were provided with fans to force air over the surfaces of the components, increasing the temperature differential between the surface of the component and the surrounding air to increase the efficiency of heat transfer. The increased temperature differential overcame some of the poor heat-conducting qualities of air.
Of all components in a computer, the microprocessor central processing unit ("CPU") liberates the most heat during operation of the computer. This springs from its role as the electrical center of attention in the computer. Thus, in prior art computers, motherboards were designed to position the CPU in the flow of air from a cooling fan; other heat-producing components were located away from the CPU to afford maximum cooling of the CPU.
As new generations of microprocessors have arrived, however, this relatively simple scheme has become decidedly inadequate, risking destruction of the CPU. It has become common to associate a heat sink with the CPU to increase the heat-dissipating surface area of the CPU for more effective cooling. Such heat sinks have a plurality of heat-dissipating projections or elements on a surface thereof (an "upper surface," for purposes of discussion). Another surface of the heat sink (the "lower surface") is placed proximate the component and a retention clip is employed to wrap around the heat sink, gripping a lower surface of the component with inward-facing projections.
Unfortunately, however, air, like electricity, takes the path of least resistance. As a result, air has a tendency to flow over and around the heatsink rather than through the fins or cooling projections of the heatsink, thus, requiring a fan having a higher airflow. To remedy this problem, shrouds have been developed to improve the efficiency of the heatsink. A conventional shroud works by limiting the area where the air can flow around the heatsink. Conventionally, a shroud comprises a three-sided, rectangularly shaped shield that is designed to fit over and around the heatsink on three sides, leaving a path through the shroud for the air to flow through the projections of the heatsink. However, even with conventionally designed shrouds, some air still travels above the heatsink, thereby reducing the efficiency of heat transfer because the conventional rectangular shape leaves room at the "upper portion" (for purposes of discussion) of the shroud. The space at the upper portion of the shroud is necessary to make the opening of the shroud as large as possible, within design limitations, to maximize the air flow through the shroud. While conventional shrouds greatly reduce the operating temperature of the CPU, the gap formed between the interior side of the shroud's wall and cooling projections, unfortunately, still allows air to by-pass the heatsink, which, of course reduces the efficiency of heat transfer from the CPU.
Accordingly, there is a need in the art for shroud that maximizes air flow capture and simultaneously increases the amount of air that passes over the heatsink. The present invention provides a heatsink shroud that addresses these needs.